Many different types of products use application-specific integrated circuits (“ASIC”) as the programmed device that runs the product. Examples include cell phones, digital voice recorders, emission systems in automobiles, audio processing devices, and image processing devices. The medical field also includes ASICs in medical devices for treating patients afflicted with disease. One particular application is in the diabetes treatment field. Glucose monitors and other handheld and portable devices for sensing and processing glucose data include ASICs. The use of an ASIC permits a smaller and lighter product and one that is much faster at reading and processing glucose data than other more conventional processors. Diabetic patients generally monitor their glucose levels relatively often to ensure that those levels are being maintained within a clinically safe range. The diabetic patient may also use this glucose information to determine if insulin should be provided or other steps taken to control the glucose level in his/her body. Today, newer glucose sensors and other medical equipment are able to produce much higher quantities of data from the biological parameter they are used to sense, and such higher quantities of data require faster processors to make efficient use of that data. The ASIC can provide that higher processing speed.
ASICs are non-standard integrated circuits that have been designed for a specific use or application. Generally an ASIC design will be undertaken for a product that will have a large production run, and the ASIC may contain a very large part of the electronics needed for that product located on a single integrated circuit. The cost of an ASIC design is relatively high and they therefore are typically designed only for high volume products. Despite the higher front-end cost, the use of ASICs can be very cost effective for many applications where volumes are high. It is possible to tailor the ASIC design to meet the exact requirement for the product and using an ASIC can mean that much of the overall design can be contained in one integrated circuit. Consequently, the number of additional components can be significantly reduced. As a result they are widely used in high volume products like cell phones or other similar applications, often for consumer products where volumes are higher, or for business products that are widely used, in additional to medical products.
With sufficient volume, custom chips, in the form of ASICs, offer a very attractive proposition. ASICs may also be used sometimes because they enable circuits to be made that might not be technically viable using other technologies. They may offer speed and performance that would not be possible if discrete components were used.
Low cost electronic products that are sold to mass consumer markets often include ASICs. Conventional ASIC methodology relies on libraries of so-called, “standard cells.” These libraries contain large numbers of pre-designed circuits (basic building blocks). When a new consumer product is designed to include one or more ASICs, a subset of the pre-designed cells is typically chosen from available libraries for inclusion in the operative circuit space of the to-be-manufactured, monolithic integrated circuit (IC) and for use in a predefined consumer application (e.g., cell phone, PDA, video/music recorder/player, etc.). After the subset of cells is selected, one or more copies of those chosen building blocks are frugally laid-out in the IC circuit space, adjacent appropriate other blocks, and they are interconnected to thereby construct more complex circuits within the IC. It is desirable to use a relatively minimal number of building blocks because IC circuit space is considered expensive. Examples of digital ASIC standard cells include multi-BIT adders, multipliers, multiplexers, decoders, and memory blocks (look-up tables). Examples of analog ASIC standard cells include amplifiers, comparators, analog-to-digital, and digital-to-analog converters. ASICs may include mixed signal designs (ICs having both analog and digital circuitry on the same substrate).
Standard cells are generally hardwired, pre-tested, and pre-designed for maximum compactness relative to the general purpose applications in which they are expected to be used. This form of optimization is not perfect though because specific ones of the general purpose applications may nonetheless call for different switching speeds, frequency ranges, voltages, currents, and fabrication technologies. So a standard cell is sometimes not the most optimally compact and efficient design for a specific application. However, it is generally adequate given the diminishing returns tradeoff for redesign and optimizing efforts. One advantage of using standard cell libraries is that there is little guess work or surprise in determining whether each standard cell will work for its intended purpose or whether it will use up far more circuit space than may generally be necessary for realizing a desired function. The cells have been pre-tested and tweaked for meeting that goal in the general sense.
When compared with alternative approaches such as using a field-programmable gate array (FPGA) or programmable logic or a programmable logic device (PLD), one outstanding advantage of using standard cells is that they tend to have much shorter signal propagating times for similar dimensions (e.g. transistor channel lengths) in fabrication technology. One outstanding disadvantage of using standard cells is that there is little room for flexibility and design change after specific ones of the hardwired cells have been chosen, judiciously inserted into the ASIC design, and connected together.
Unfortunately, consumer markets tend to be very fluid and changing. One day, the consuming masses want one kind of function in a product and the next day, perhaps simply due to whim, they change their minds and demand a very different kind of function. An analogous situation exists in the medical field with handheld instruments; however, often for another reason. In the medical field, as a disease and its effects become better understood, different ways of analyzing patient data are found to be more effective in diagnosing and treating patients. New algorithms may be developed for both analyzing data and presenting it to physicians or other health care professionals for their use in treating a patient. This can be a problem for those desiring to use an ASIC in their products. A warehouse full of what, on one day is a highly-demanded product (with an incorporated ASIC into that product), can become worthless overnight as new technology becomes available.
ASICs and other devices utilize locally-stored programming or “software” to perform a number of measurement, data collection, data analysis, and other application-related functions. This software can be stored, at least in part, in non-volatile memory within the device. One such non-volatile memory is read-only memory (ROM), which provides advantages in cost, power efficiency, speed, and reliability, among others. Software that is stored in ROM is electrically and physically designed into the memory layout during the semiconductor manufacturing process, i.e., the software is permanently coded in the ROM. The software therefore cannot be altered after the semiconductor device has been manufactured. The introduction of a software revision can only be accomplished by redesigning the semiconductor device, producing a revised layout, assembling new photolithography masks, and fabricating entirely new semiconductor chips, which is a lengthy and expensive process. It may also require those semiconductor devices that were already assembled to be discarded.
The introduction of revisions to ROM-based software code may not be a significant concern in industries where the software functions are relatively simple and software development occurs at a relatively slow and measured pace. However, analyte monitoring applications can be complex and continually evolving as ever more research and resources are devoted to improving the health and lifestyle of patients. They are also subject to governmental regulations that can be introduced, changed, or interpreted in ways that require modifications to the operation of the analyte monitoring devices.
By way of a more specific, but hypothetical, example consider a case where a circuit designer has elected to use a first kind of data-inputting standard cell in his ASIC for processing input data streams (RF wireless transmissions, as an example) according to a corresponding, first industry standard protocol, call it, decompression “algorithm A.” Industry experts have voted this “algorithm A” as being the best. However, after the ASIC is put into mass production, market forces are such that the majority of customers change their minds and decide they want a product that instead uses a different and incompatible input processing protocol, decompression “algorithm B.” A popular journalist may have indicated he likes B better and suddenly consumers are demanding products that use decompression algorithm B. In such a case, the mass-produced ASICs that the designer has in his warehouses become essentially un-saleable. They work, but the market has now shrunk. If the marketing manager had had the foresight to instruct the circuit designer to use a second data-inputting standard cell that processes input data streams according to the competing, decompression “algorithm B” in his ASIC design instead of using the “algorithm A” block, the product would still be viable. However in this case, the hard-to-predict changes in future market trends was in fact not predicted. As a result, his company is not able to sell more than a few of the algorithm A chips to what few customers are using algorithm A. Often, so-called network effects for interoperable devices are at work. Although algorithm A is a reasonable and perhaps a better choice, unpredictable market forces often come into play and allow an incompatible and alternate standard (algorithm B) to take an initial and commanding lead. This initial lead eventually translates into algorithm B becoming the dominant one in the given market space. The classic example is the BetaMax® versus the VHS® format battle that played out in the video-cassette recorders markets (VCR markets).
In order to deal with the unpredictable shifts in consumer demand, some designers have suggested shifting to the use of in-field fully-programmable logic or analog devices. Field programmable devices such as field-programmable logic devices (FPLD), field-programmable gate arrays (FPGA), complex programmable logic devices (CPLD), and others in the digital world are the antithesis of the full-ASIC approach. Essentially all of the circuitry in an FPLD is reprogrammable such that it can implement alternative functions. Thus the incompatible programming problem can be obviated by allowing for programmable downloading of one or the other of the incompatible options. Manufacturers can theoretically load into their fully-programmable chips whichever of the competing protocols wins in the marketplace. The problem with the field-programmable approach however, is that the fully-programmable circuitry tends to be more expensive, larger in size, slower in response time, and prone to various problems from which ASIC circuitry does not generally suffer. One sample problem is that of having flawed software loaded into one or more of the many configuration memory cells (or fuses or anti-fuses) of a field-programmable device. Then the fully programmable device fails to work properly just because of the flaw. However, an ASIC standard cell is basically not programmable (not programmable to the same generic extent as are the counterpart, fully-programmable gate arrays) and it is not prone to the wrongful configuration problem. Also, the ASIC design does not need to consume as much circuit space, electrical power, and/or signal routing resources as does a fully-programmable (or fully re-programmable) field device for supporting configuration memory and its programmability or re-programmability. Thus the ASIC solution tends to be more reliable, more compact, and more energy efficient.
A movement also existed towards a mixed genre referred to as “hybrid” ASIC-FPGA. The idea is to have some circuitry implemented as ASIC standard cells and other operative circuitry implemented as fully-field-programmable gate arrays. The specific mix and nature of such hybrid approaches are not well defined and have not overcome the problems of reduced speed and reliability.
The limited configurability of ASIC designs continues to be the benefit of ASICs and the problem. They may be programmable via control registers, but they use fixed architectures. These fixed architectures do not allow for functional modules to be re-arranged or reconfigured by a user. ASICs such as field programmable gate arrays (“FPGAs”) permit the user to reconfigure or reprogram functional modules, however, they are an extreme example which requires a great deal of specialized programming and a special, fine-grained ASIC architecture to implement. Another attempted solution to programming ASICs is the use of a cross-point switch, such as that described in U.S. Pat. No. 7,809,347 to Yancy. However, this design also has disadvantages.
Hence, those skilled in the art have recognized the need for ASIC devices, the programming of which can be altered in the future in the event that changes are required. A need as also been recognized for a more simple approach to reprogramming ASIC devices to preserve the architecture of the ASIC while at the same time, providing for a different output from its use. The following subject matter fulfills these needs and others.